JAVA 设计模式 享元模式

abstract class Flyweight {
    public abstract void Operation(int extrinsicstates);
}

class ConcreteFlyweight extends Flyweight {
    @Override
    public void Operation(int extrinsicstates) {
        System.out.println("共享的Flyweight : " + extrinsicstates);
    }
}

class UnsharedConcreteFlyweight extends Flyweight {
    @Override
    public void Operation(int extrinsicstates) {
        System.out.println("不共享的Flyweight : " + extrinsicstates);
    }
}

class FlywightFactory {
    private Hashtable<String, Flyweight> flyweights = new Hashtable<String, Flyweight>();
    
    public FlywightFactory() {
        flyweights.put("X", new ConcreteFlyweight());
        flyweights.put("Y", new ConcreteFlyweight());
        flyweights.put("Z", new ConcreteFlyweight());
    }
    
    public Flyweight GetFlyweight(String key) {
        return ((Flyweight)flyweights.get(key));
    }
}

public class FlyweightPattern {
    public static void main(String[] args) {
        int extrinsicstates = 1;    
        FlywightFactory factory = new FlywightFactory();
        
        Flyweight fx = factory.GetFlyweight("X");
        fx.Operation(extrinsicstates);
        
        Flyweight fy = factory.GetFlyweight("Y");
        fy.Operation(++extrinsicstates);
        
        Flyweight fz = factory.GetFlyweight("Z");
        fz.Operation(++extrinsicstates);
        
        Flyweight uf = new UnsharedConcreteFlyweight();
        uf.Operation(++extrinsicstates);
    }
}